Hamilton Quarry is a Late Carboniferous lagerstätte near Hamilton, Kansas, United States. It has a diverse assemblage of unusually well-preserved marine, euryhaline, freshwater, flying, and terrestrial fossils (invertebrates, vertebrates, and plants). This extraordinary mix of fossils suggests it was once an estuary. This type of Lagerstätte is considered a Konservat-Lagerstätte (or conservation lagerstätte), due to the quality the preservation of soft tissue (skin preservation).

The lagerstätte occurs within a paleovalley that was incised into the surrounding Carboniferous cyclothemic sequence during a time of low sea level and was then filled in during a subsequent transgression. The channel has a capping series of interbedded laminated limestones and mudstones for which are designated the Lagerstätte beds or ‘vertebrate horizon’. This facies contains a well-preserved mixed assemblage of terrestrial (conifers, insects, myriapods, reptiles), freshwater (ostracods), aquatic (amphibians, reptile), brackish or euryhaline (ostracods, eurypterids, microconchids, fish), and marine (brachiopods, echinoderms) fossils.

Paleobiota

According to thesis^[1]

Vertebrates

Vertebrates
Genus	Species	Notes	Images
Orthacanthus	Indeterminate	Elasmobranch in order Xenacanthida.
Expleuracanthus	E. cf. E. parallelus
Xenacanthus	Indeterminate
Hamiltonichthys	H. mapesi	A Hybodont elasmobranch.
Petalodus	Indeterminate	A petalodont holocephalian.
Acanthodes	A. bridgei	An acanthodiform acanthodian.
Elonichthys	Indeterminate	A palaeonisciform actinopterygian.
"Feroniscus"	"F. hamiltoni"/"F. hamiltonensis"	A palaeonisciform actinopterygian, nomen nudum (Only described in thesis).
Gnathorhiza	Indeterminate	A lungfish.
Sagenodus	S. cf. copeanus
Eoscopus	E. lockardi	An amphibamiform temnospondyl.
Euconcordia	E. cunninghami	A captorhinid.
Spinoaequalis	S. schultzei	An early semi-aquatic diapsid.
Archaeovenator	A. hamiltonensis	A varanopid.
Eocasea	E. martini	A caseid synapsid.
Ianthasaurus	I. cf. I. hardestii/hardestiorum	An edaphosaurid synapsid.
?Lupeosaurus	Indeterminate

Arthropods

Arthropods
Genus	Species	Notes	Images
Prothelyphonus	Indeterminate	A whip scorpion.
Archaeoctonus[2]	A. cf. A. glaber	A scorpion. Multiple papers misspelled as Archaeoctonous.[3][4]
Adelophthalmus	A. cf. A. mazonensis	An adelophthalmid eurypterid.
Amphissites	Indeterminate	Ostracod.
Geisina
Gutschickia
Bairdia
Pseudobythocypris
Carbonita
Darwinula
Paromylacris		A roachoid.
Oedischia		An orthopteran.
Meganeura		Meganisopteran.
Titanophasma
Carrizopteryx		A palaeodictyopteran.

Mollusks

Other animals

Lycophytes and ferns

Lycophytes and ferns
Genus	Species	Notes	Images
Sigillaria	S. brardii	A tree-like lycophyte.
Asterophyllites	A. equisetiformis, A. longiformis	Equisetid fern.
Annularia	A. mucronata
Paleostachya	P. sp.

Seed ferns

Seed ferns
Genus	Species	Notes	Images
Sphenopteris	S. cf. S. germanica	A seed fern.
"Callipteris"	C. conferta, C. flabellifora, C. scheibei	A seed fern in order Peltaspermales.
Cyclopteris	Indeterminate	Seed plant in order Medullosales.
Neuropteris	N. sp. (two species)
Odontopteris	Indeterminate
Trigonocarpus	Indeterminate	A seed fern seed.

Gymnosperms

Gymnosperms
Genus	Species	Notes	Images
Cordaites	C. principalis	Gymnosperm in order Cordaitales.
Cordaianthus	C. cf. pitcairniae
Samaropsis	S. fluitans
Emporia	E. cryptica, E. lockardii, E. royalii	Conifer in order Voltziales.
Hanskerpia	H. hamiltonensis
Barthelia	B. furcata
Gomphostrobus	Indeterminate	Conifer in order Voltziales, stem and leaf.
Walchia	W. hypnoides, W. piniformis, W. schneideri	Conifer in order Voltziales, leaves.
Walchianathus	Indeterminate	Conifer in order Voltziales, male cone.
Walchiastrobus	Indeterminate	Conifer in order Voltziales, female cone.

Spores and Pollen

Fuslinids